Electrophotographic copying apparatus



NOV. 6, C. R. MAYO ELECTROPHOTOGRAPHIC COPYING APPARATUS 4 Sheets-Sheet1 original Filed Feb. 7, 1955 ATTORNEY Nov. 6, 1962 c. R. MAYo 3,062,108

ELECTROPHOTOGRAPHIC COPYING APPARATUS Original Filed Feb. 7, 1955 4Sheets-Sheet 2 INVENTOR.

Clyde R. Mayo ATTORNEY.

Nov. 6, 1962 C, R, MAYO 3,062,108

ELECTROPHOTOGRAPHIC COPYING APPARATUS Original Filed Feb. 7, 1955 l 4Sheets-$1681. 3

Fla 5 30d mvENroR.

Clyde R.Mayo

Afro/mfr Nov. 6, 1962 c. R. MAYO 3,062,108

ELECTROPHOTOGRAPHIC COPYING APPARATUS Original Filed Feb. 7, 1955 4Sheets-Sheet 4 INVENTOR. Clyde R. Mayo United rates 3,062,108ELECTROPHOTOGRAPHIC COPYING APPARATUS Clyde R. Mayo, Rochester, N.Y.,assignor to Xerox Corporation, a corporation of New York Originalapplication Feb. 7, 1955, Ser. No. 486,513. Di-

vided and this application Dec. 29, 1958, Ser. No.

This invention relates in general to xerography and, in particular, toapparatus and mechanism for implementing the xerographic process and forprojecting an original to a moving surface such as a rotating cylinderor a moving plate. This application is a division of copending Mayoapplication Serial No. 486,513, filed February 7, 1955, now abandoned.

In Carlson Patents 2,297,691 and 2,357,809 there is disclosed anelectrophotographic process, since known as xerography, and apparatusand mechanism for this process. The apparatus and machines heretoforedeveloped in accordance with the Carlson invention have been manual inoperation and relatively time-consuming. Accordingly, it is an object ofthis invention to provide a xerographic machine or apparatus capable ofoperating to produce a completed xerographic print in a matter ofseconds after original exposure and to repeat the process steps so thata further xerographic copy can be reproduced immediately thereafter witha total cycle time in the order of fractions of a minute.

It is a further object of this invention to provide that the exposure ofan original to be copied be made to a sensitive moving surface, whethera rotating cylinder or a moving plate, wherein the original to be copiedis positioned above a lens system arranged to fix an image of theoriginal on to the moving sensitive surface which in turn is spacedapart from the lens, and where proper registration of the image of theoriginal is made upon the moving surface by having the lens move inrelation to the original.

It is a further object of the invention to provide a xerographic machinecapable of operating to reproduce a copy from an original selectively,either one copy of the original or a plurality of copies of the originaland to form such copies repetitively in quick succession.

It is still another object of the invention to provide a xerographicmachine comprising a rotating cylinder having at least a portion of itssurface electrophotographically sensitive, such cylinder rotatingthrough a charging station, an exposure station, a developing station, apaper yfeed and transfer station, and, if desired, a cleaning stationand a regenerating station whereby a xerographic image is produced bythe successive steps of exposure, development, and transfer. It is afurther object of this invention to provide for the use of this machinein connection with slit projection and in such case to arrange forsuitable and even lighting and also to provide for the motion of thelens and other parts in a way to avoid vibration thereof.

Another object of the invention is to provide apparatus and mechanismfor reproducing automatically a representation of a visible image fromthe face of a cathode ray tube.

Additional objects of the invention will be understood from thefollowing specification and from the drawings in which:

FIGURE 1 is a front elevation of a xerographic machine according to anembodiment of the invention;

FIGURE 2 is a rear elevation, partly in section, of a machine shown inFIGURE 1;

yFIGURE 3 is a rear elevation, partly in section, illus- 3,062,108Patented Nov. 6, 1962 ICC trating the mechanism provided for thedevelopment station;

FiGURE 4 is a View of a corona charging electrode according to oneembodiment of the invention;

FIGURE 5 is a plan view of an alternative form of projection slitadvantageously employed under certain circumstances;

FIGURE 6 is a side View, partly in section, of a preferred form of lenscarriage and actuating mechanism;

FIGURE 7 is a transverse view, partly in section, along the lines of7--7 shown in FIGURE 6;

FIGURE 8 is a side view of an alternative embodiment of the inventionshowing a preferred form of uniform lighting by having the light sourceconnected to and movable with the slit-provided carriage; and

FIGURE 9 shows an embodiment of the invention in connection with thereproduction of the visible image from the face of a cathode ray tube.

Referring more particularly to FIGS. l and 2, a xerographic machinegenerally designated 10 consists of a cylindrical member 11 providedwith a xerographically sensitive surface. Around the cylinder areassembled the various stages of operation for the xerographic process.These stages include an exposure station 12, a developing station 13,and a regeneration station 14, paper feed station 15, transfer station16, and a cleaning station 17 followed by a charging station 18.Positioned above the exposure station and spaced apart are a movablelens system 19 and a fixed support 20 for the original or master to becopied, together with a slit projection arrangement and a source oflight 9, for example, sun lamps, operating preferably on the reliectedback or opaque system.

At the exposure station, generally designated 12, is a hood or bellowsor other shield 21 adapted to protect the xerographic surface fromextraneous light and having'a slit 22 at its lower portion adjacent tothe surface. The upper end of this shield 21 is open to receive anoptical image from a master or original as described hereinafter.Closely adjacent but spaced from the shield and positioned above it is aslotted track 24 on which is mounted a carriage 25 supporting andcarrying a lens 26 which is thereby movable above and across the Lipperend of the shield 21. Spaced above this track 24 is a second track 28,likewise bearing a carriage 29, which carriage has a transverse slit 30extending thereacross. Preferably, for ease of motion, both of thesecarriages may be mounted on balls 27 and wheels 31 respectively or othermeans or mechanism may be employed to cause these carriages to move orslide easily and smoothly along their track. To avoid vibration of thelens while it is moving, it bas been found desirable to mount the lens(see FIGS. 6 and 7) in a heavy metallic carriage 25 and to employchannels 32 formed in the heavy metal carriage 2S for the lens and intrack 24, and by positioning for use in the channels four metal balls27, held in place by a suitable bearing cage (not shown). This heavymetal and ball construc tion can be machined to a high degree ofperfection to avoid the vibration of the lens.

Positioned above the upper track 23 is a fixed support 2t) consisting,for example, of a copy board 33 which may consist of a transparent planemember such, for example, as a glass plate or the like, which is adaptedto receive a master or original placed face downward, on its uppersurface, in position for having its image projected through the lens onto the sensitive surface of the cylinder 11, and positioned over thecopy board 33 is a flexible copy cover 23, made, for example, ofplastic, for holding copy fiat against the upper surface of the copyboard.

In order to provide for correlated motion of the lens carriage 25 andslit-provided carriage 29 in their travel across the respective tracks24 and 28, whereby an optical a image from the original placed facedownwardly on copy board 33 can be projected onto the photosensitivesurface of the cylinder 11 in proper coordination with the rotation ofthe cylinder, there is provided the following carriage-actuatingmechanism: Partial gear 34 is integrally a part of the cylinder oroptionally is integrally mounted on an axle 35 with which the cylinderrotates. Adjacent to this partial gear is a cam 36 integrally a part ofthe cylinder or optionally integrally mounted on the axle 35.

Adjacent to the partial gear 34 is a gear wheel 37 mounted on orconnected with a first or inner pulley wheel 38 and a second or outerpulley wheel 39. The relative sizes of partial gear 34, gear wheel 37,the inner pulley wheel 38 and of pulley wheel 39 are coordinated andrelated so that the circumference of pulley wheel 39 rotates at the samespeed as the circumference of cylinder il, while the inner pulley wheel38 is of one-half the diameter of pulley wheel 39, whereby itscircumference moves at onehalf the linear rate of the motion of cylinder1l. Cam arrangement 36a, fixed to gear 37, cooperates with cam 36 togive to the lens assembly a gradual start. Around the circumference ofpartial gear 34 are gear teeth 40 extending along to a length such thatpulley 39 is driven through a distance equal to the maximum length ofcopy which is to be produced from the original on copy board 33.Flexible tapes 41 and 42 are secured to the circumference of pulleys 38and 39, respectively. Tape 41 passes over freely movable wheels 44positioned in line with track 24 and extending therebeyond to a carriagereturn mechanism which may, for example, be a weight 45 suspended at thefree end of tape 41. In a similar manner, tape 42 passes over freelymovable wheels 46 in line with track 28 and is secured to a returnmechanism which likewise may suitably be a weight 47 secured to the freeend of tape 42 after it passes over wheel 46. Tapes 41 and 42 in turnare secured by fasteners 48 to carriages 25 and 29, respectively,whereby linear motion of the tapes draws the carriages along theirtracks at a corresponding rate of speed.

yFrom the foregoing, it can be seen that a single rotation of partialgear wheel 34 causes a partial rotation of pulleys 3S and 39 with theconsequent winding up of tapes 41 and 42 across the pulleys, causingcarriages 25 and 29 to be drawn across their tracks, carriage 25 at arate of speed equal to one-half the rate of speed of the surface ofcylinder 11 and carriage 29 at a speed equal to the speed of cylinder11. Upon completion of the drive motion, completed by the release ofpartial gear 34 from gear 37, the carriage return mechanisms, that is,weights 45 and 47, return the carriages to their original positions inpreparation for another cycle of operation. It is apparent, therefore,that during the drive phase of the cycle an optical image from theoriginal placed on copy board 33 is projected through lens 26, suchprojected image passing through slit 22 on to the surface of cylinder 11in mirror-image relation such that the image received by the movingcylinder surface is a true projected image of the original to be copied.

In the case of slit projection, it is important that uniform lighting beprovided during the projection. The source of light 9, which may be sunlamps, is suitably located to provide for reflected-back or opaqueprojection between the lens and the original to be copied. It isdesirable to illuminate all areas of the slit uniformly during all partsof the cycle of projection. Accordingly, the sun lamps or other sourceof light 9 may be connected with the movable carriage 29 carrying theslit 30 so that movement of the carriage and slit results incorresponding movement of the light, resulting in uniform lighting ofthe slit at all times. Such a system is illustrated in FIG. 8. Thecarriage Z9 traveling in track 28 is provided with copy board 33 onwhich the original to be copied may be placed face downwardly. Sun lamps9 are axed to the carriage by means of bracket 9b positioned below theslit 30 to provide for the reflected uniform lighting of the iprojection slit during the transverse movement of the carriage.

The size of the apparatus disclosed may be reduced with the use of awide angle lens. In such case, it may be that a certain amount of unevenlighting of the slit is necessary. A form of slit that may beadvantageously employed is illustrated in FIG. 5. Such a slit 30]; isprovided with greater Width at its extremes 30C than at its center 30d.This form of slit may also be profitably employed in connection withslit projection where diliiculties due to uneven lighting may beencountered.

It is to be noted that the apparatus described herein may be used forreproductions of the same size as the original or for larger or smallersize as may be desired. When one-to-one reproductions are to be made,the lens will be positioned halfway between the photographicallySensitive moving surface and the original to be copied. When smallerreproductions are desired, then the lens is positioned closer to thephotographic surface than to the original. For example, when the lens islocated at onethird the distance from the surface to the original, thena reduction in the reproduction to one-half is accomplished. In theopposite way, larger reproductions may be produced.

In the copying machine herein described, when adjustment of the spacingof the lens between the sensitive surface and the original is made, acorresponding adjustment of the linear distance through which the lenscarriage 25 and the carriage 29 provided with a transverse slit shouldalso be made. For example, when the lens is positioned one-third thedistance from the plate to the fixed position of the original as when ahalf-sized reproduction is desired, the lens should move one-third ofthe distance that the slit moves through. The rate of speed of the lensto that of the motion of the slit must therefore be adjustedaccordingly. In the machine described, this adjustment may be effectedby suitable designing of the size of the respective gear wheels 34 and37 or the pulleys 38 and 39. Automatic means controlling the movement ofthe lens and the slit under these different circumstances may beprovided so that simple and expedient means may be used to produce,respectively, one-to-one reproduction, enlargement and reductions usingthe slit exposure system shown. As a general rule, the slit should besmall with respect to the diameter of the drum. It has been found that,in the case of a l5 to 30 inch diameter drum, the slit may be adjustedup to one inch to achieve proper radiation intensity.

Disposed adjacent to the exposure station 12 and directly subsequentthereto in the direction of rotation of cylinder 11 is the developmentstation 13 comprising essentially a developing hopper 51 adapted toreceive and contain a charge of a developing material for a xerographicprocess. Preferably, the developing hopper has side walls 52 andtapering bottom walls 53 which lead down to a discharge orifice 54. Aclosure member or gate 55 is mounted, for example, pivotally on asupport 56 so as to open and close discharge orifice 54. The motion ofthis gate 55 is controlled by suitable means such, for example, as anelectrically operated solenoid 57 which may cause the gate 55 to bepivoted on its support 56. Preferably, a batiie 59 is adjustably locatedadjacent to the discharge orifice 54 and is positioned and adapted tocooperate with gate 55 in closing the developer hopper 51. When the gate55 is in its open position, it is close to but free from contact withthe surface of cylinder 11. Baflie 59 and gate 55 are disposed andpositioned to direct the ow of developer material from the hopperagainst the surface of cylinder 11.

Desirably, the developer hopper 51 is disposed and located near theupper portion of the cylinder in such position that the developermaterial which is delivered from the hopper falls to the surface of thecylinder at a position where the surface is relatively near to thehorizontal but at a definite angle from the horizontal. Thus,

for example, it is desirable that the developer material from the hopperfall upon the cylinder where the cylinder surface is at an angle betweenabout and 45 from the horizontal so that the material can cascade orroll across the surface of the cylinder for a substantial distance incontact with the surface.

At the next subsequent position around the cylinder and preferablylocated at or below the axis of the cylinder is a developer catcher 60which may still be regarded as part of the developing station. Thisdeveloper catcher may be provided with a catching chute 61 positionedand adapted to catch and receive the development material cascading fromthe hopper across and along the surface of the cylinder and adapted toconvey and direct the devel- Oper material to a mixing chamber 62.According to one embodiment of the invention, the mixer 62. is in theform of a cylindrical tumbler mounted at an angle of about from thehorizontal and having a plurality of vanes 63 (FIG. l). The mixer ismounted on bearing supports 65 adapted to be rotated by suitable drivemechanism (not shown) and feeds into a bucket type return elevatorcomprising a belt 66 carrying buckets 67 around lower and upper wheels69, the whole elevator mechanism being contained within a shield orcasing 70. At its upper end, the bucket elevator feeds into a returnchute 71 which in turn feeds the development material into`the'developer hopper 51 for a repetition of the cycle. At anotherstation around the cylinder 11,- it may be desirable to have a reversecharging or regeneration station at which a charge is applied to thesensitive surface, the charge being of polarity opposite to that whichis applied for the initial sensitizing step described hereafter. Thus,optionally, a reverse charging or regeneration station 14 may bepositioned next subsequent to the developer station in the direction ofrotation of the cylinder and prior to the proper feed and transferstations 15 and 16. In the reverse charging station, generallydesignated as 14 (see FIG. l), there is provided a suitable chargingmember such as a corona discharge electrode 72 consisting of one or moreline conductive strands for corona discharge wires 73, controlelectrodes 75, and preferably a ground plate 74 similar to the chargingelectrode 136 to be described hereinafter.

Positioned next and adjacent to the regeneration station is acopy-feeding station provided with suitable sheetfeeding mechanismadapted to feed sheets of paper successively to the cylinder 11 incoordination with the presentation of the developed image at thecopy-feeding station. This sheet-feeding mechanism includes a sheetsource 81 such as a tray for a plurality of sheets 82 of a suitabletransfer materialthat is, typically, sheets of paper or the likeand apair of feed rollers 83 and 84 adapted to direct the sheet material intocontact with the rotating drum at a speed preferably slightly in excessof the rate of travel of the surface of the drum. One of these rollers83 is a driven roller operated by a chain of gears 86, 87 and 88, drivenin turn by a gear S9 integrally connected with the rotating cylinder 11.Preferably, gear 89 is a partial gear whereby the paper feed rollers 83and 84 are driven only during the portion of the cycle where it isdesired to feed the sheet material to the surface of the drum. A feedingfinger 91 is driven by a shaft 92, which in turn is operated by arm 93,pivotally secured to fixed support 94, the arm 93 being energized by afeeding member or cam follower 95, driven by cam 96, whereby the feedingfinger 91 is adapted to feed the top sheet of the stack 82 to the feedrollers 83 and 84 in coordination with the appearance of the developedimage at the paper feed station as may be determined by the cam 96. Inthis manner, the sheet material is introduced between the feed rollersand is thereby brought into contact with the rotating cylinder 11 at thecorrect time and position to register with the developed image.

Preferably, `at the exact point of contact between the sheet materialand the rotating drum, a transfer station 16, consisting of a coronadischarge electrode, is positioned to effect transfer of the developedimage from the cylinder surface to the sheet material. The transferelectrode consists essentially of one or more corona discharge wires 97and control electrodes 99 positioned and disposed above a ground platel98 substantially similar to the discharging electrode 18 to bedescribed hereinafter. The sheet-feeding and transfer mechanism aresimilar to the type disclosed in Mayo et al. Patent 2,684,902 filedNovember 23, 1951. Immediately subsequent to the transfer station `16are positioned strip lingers 181 operated by arm 102, in turn energizedby cam member or follower 103 driven by a second cam 104 integrallymounted on or connected with the rotating cylinder 11. These strip orpick-off fingers are adapted to be brought into contact with the surfaceof the cylinder 11 slightly in advance of the sheet material and tostrip the sheet material from the cylinder surface, directing the freesheet material into a fixing mechanism generally designated 105 andfurther defined in a copendirig application Serial No. 232,152, filed.lune 18, 1951, now Patent No. 2,7101] 65 The fixing apparatus disclosedin FIG. 2 consists essentially of a heated rotating drum 111 and acorona discharge electrode 112 or the like, spaced closely adjacentthereto and adapted to receive the sheet material therebetween, wherebythe sheet material is secured by electrostatic adhesion to the surfaceof the heated drum, and the developed and transferred image is fixedthereon by conducting heating from the surface of the drum through thesheet transfer material. Cylinder 111 preferably is contained within ahousing 113 and is driven by motor 113' operating through drive Wheel114 and belt 11S to drive the heating cylinder at a rate whichoptionally may be the same as that of the rotation of cylinder 11.Sliding pick-off fingers 116 serve to pick the sheet material from thesurface of heated drum 111 and direct it into a tray 117 wherein thecompleted xerographic print is collected and stored. Y Positioned nextsubsequent to the transfer and pick-up station is a cleaning stationgenerally designated 17, at which is disposed cylindrical brush 121rotatively mounted, for example, on axle `122 and adapted to be drivenby a motor y123 operating through belt 124. The entire cleaning sectionis mounted within a housing 125 with a sub-housing or hood 126surrounding the cylindrical brush as disclosed and illustrated in FIG.2. The cylindrical brush may consist, for example, of rabbit fur securedon the surface of a solid or structural cylinder 127 and be rotated in adirection opposite to the direction of rotation of the cylinder surfaceat the point of contact, so that the relative motion between the brushsurface and the cylinder surface is the sum of the two separate speedsof motion. A filter member 128 may be positioned in one wall of thehood, preferably the lower wall thereof, to permit passage of airtherethrough but at the same time to collect dust or electroscopicparticles removed from the surface of the cylinder by the brush. In themechanism as illustrated in FIG. 2, the brush fibers, due to the highcentrifugal force caused by the rotating motion, extend outwardly untilthey reach in contact the cylinder surface, when they are somewhatdepressed. Immediately upon release, the brush fibers extend outwardlyagain from the surface, thus causing a vane-like action which causes aliow of air into the hood area at the space between the hood and thecylinder and out through filter 128. `In this manner, a constant flow ofair serves to free the brush fibers from electroscopic particles pickedup by the cleaning action and thus to maintain absence of dust in thesurrounding atmosphere. If desired, this air flow action may besupplemented through the use of a supplemental vacuum flow from anairblower or the like (not shown).

Next subsequent in the direction of rotation of cylinder 11 isoptionally positioned a light discharge source such, for example, as aneon light 1311 placed directly over the 7 surface of the cylinder 11and adapted to flood the entire surface of the cylinder with light priorto its entering into the next subsequent process stage of charging. thusassuring at this point complete photoconductive dissipation of anyresidual electric charge from the photoconductive sensitive surface ofthe cylinder.

The nal stage through which the rotating cylinder surface passes, whichstage may be considered as an initial stage of this or a subsequentcycle, is a charging station 18 wherein the cylinder surface is adaptedto pass under a corona discharge electrode, generally designated at 130in FIG. 2, consisting of one or more ne conductive strands or coronadischarge wires 132, optionally with a ground plate 33 at leastpartially surrounding the wires. Control electrodes 134 are providedbetween the discharge wires 132 and the surface of cylinder 11 wherebythere occurs a ow of gaseous ions from the wires to the cylindersurface. This corona discharge is of the type described and claimed incopending application Serial No. 221,582, now Patent No. 2,778,946.

Cylinder or drum 11 around which are stationed the various stages of thephotographic process provides a cylindrical support surface of anelectrically conductive material such, for example, as a metal surfaceor the like, on which is placed a photoconductive insulating layer such,for example, as a layer or coating of vitreous selenium or otherphotoconductive insulating material. Suitable for this purpose arevarious photoconductive insulating compositions characterized by anextremely high specific resistivity in the absence of illumination,which resistivity drops at least several orders of magnitude uponexposure to bright light. Suitable material, in addition to seleniumcompositions, include, for example, anthracene, sulphur,sulphur-selenium mixtures and the like, as well as other photoactivematerial characterized by high insulation in the dark and byphoto-initiated conductivity such, for example, as photoactivation ofelectrons in the molecular structure to a conductivity band or by othertransitory or permanent change in conductivity upon exposure to light.It is to be understood that the cylinder 11 may be a cylinder surfacehaving a photoconductive insulator directly on its surface or may, ifdesired, have a support member adapted to receive and support incylindrical configuration one or more separate xerographic membersconsisting of a conductive backing and a photoconductive layer thereon.Then, if desired, the drum or light member may be directly coated with avitreous selenium composition or, alternatively, a rigid or flexiblexerographic member may be suitably secured to the surface of acylindrical support member.

In the device and apparatus disclosed in the drawings herein, thevarious mechanisms connected with the stations of exposure, paperfeeding, paper pick off, and the like, are controlled by a single unit,gears and partial gears, and by single unit cams, and therefore areadapted to cooperate with a cylinder or drum containing a singlexerographic member or a single xerographic station at its surface. It isto be understood, however, that a plurality of such members or stationsaround the cylinder may be employed and that a plurality of partialgears, cam members, and the like may be used in cooperation therewith,whereby two or more separate xerographic cycles may be accomplished in asingle revolution of the cylinder or drum 11. Such an arrangement may bedesirable under certain circumstances and be adapted for a plurality ofcycles in a single cylinder revolution.

In the disclosure of the preferred form of embodiment of the invention,a cylinder or drum has been employed to provide a movable photosensitivesurface. Such a movable surface may be secured in other ways, such as amovable plate or belt and the invention is also applicable thereto.

The mechanism disclosed herein is suitable for the reproduction of oneor more copies of an original placed on the copyboard 33. By suitablemeans, such as handpositioning or by mechanical means, the desiredoriginal material is placed on the copy board. The cylinder is thenenergized and exposure takes place with the carriages 2S and 29 passingacross the surface of the copy in synchronized motion and correlatedspeed according to the rotation of cylinder 1l. rIhe exposed portion ofthe surface of the cylinder then passes into the developing stationwherein a suitable developed material is cascaded across the surface andis collected by the developer catcher and returned to the developerproper. The exposed and developed portion of the surface of the cylinder11 then passes to the paper-feeding station and the transfer stationwhere it receives a sheet of transfer copy material and passes under acorona discharge whereby the developed image is transferred to the paperor other transfer member. rhe cylinder, with the adhering transfersheet, then passes to the pick-up lingers 101 where the sheet isstripped from the cylinder surface and enters the xing chamber whereinthe transferred image is fixed to the transfer sheet by heat fusing orthe like. The cylinder surface then passes to the cleaning station whereany residual powder is removed by brush 121 and then after coming underdischarging light `131 the surface passes to the charging electrode d3@where an electrostatic charge is deposited on the surface of the drumand the drum is thus sensitized or re-sensitized and prepared for thesucceeding exposure and development cycle. At this stage, if more thanone copy is desired, the cycle is repeated until suiiicient copies areobtained, whereupon a different original is placed on the copy board andthe cycle then repeated as desired.

According to the presently preferred procedure, the developmentcomposition employed includes a two-component developer consisting ofgrossly larger carrier particles and fine electroscopic powderparticles, coated on the surface thereof such, for example, as describedin Patent No. 2,618,551. As the process continues through the repetitivecycles, the quantity of electroscopic powder material in the combinationdeveloper may become depleted and it accordingly is desirable toreplenish the developer composition with additional electroscopicpowder, either continuously or from time to time. The replenishment ofthe developer composition may be achieved by adding to the developermixture in the tumbler 62 or immediately prior thereto a smalladditional quantity of the electroscopic powder material. The additionof this small quantity of developer powder may be accomplished manuallyor, if desired, by automatic means by a replenisher opening 62a as shownin FIG. l. The developer composition with the replcnishing powder ismixed in tumbler 62, whereupon uniform intermixing is achieved and thecornbination developer is then re-cyled into the developer hopper forre-use through one or more succeeding xerographic cycles.

According to a further embodiment of the invention, the mechanism asherein described is adapted for the reproduction of an optical imageformed on the face of a cathode ray tube or like source of conversion ofenergy. A suitable embodiment of this mechanism may be that disclosed inconnection with FIGS. l and 2 wherein the face of the cathode tube issubstituted for the original 20 to be copied as shown in those figuresor an embodiment such as shown in FIG. 9 wherein the lens 26 is kept inconstant position over the exposure section 12 of the cylinder 11 and isnot caused to travel back and forth across the exposing station. In thismodification, a cathode tube 9@ with its face 90a is held above theshield Z1 of the exposure section which in turn is located above therotatable cylinder 11. The photosensitive surface of the cylinder 111rotates through the exposure station 12 and then through correspondingdeveloping station, paper feed station, transfer station, cleaningstation, and charging station, all as disclosed in FIGS. 1 and 2. Anelectrical image is fed to the cathode ray tube according toconventional electronic circuits, to yield an image on or a movingacross the face of the tube in coordination with the rotation of thecylinder. This optical image is projected'and focused on to theelectrophotographieally sensitive cylinder surface to form thereon anelectrostatic latent image which in turn is developed and transferred tocopy sheet materialor the like, all as previously described and shown inconnection with FIGS. 1 and 2. When a cathode ray tube or like source ofan optical image is employed in conjunction with the vitreous seleniumtype of the Xerographic surface, it is preferable that the face of thecathode ray tube contain a phosphor, preferably one which is relativelyhigh in spectral sensitivity in the blue-green range, this presentlybeing the spectral range of greater sensitivity for the vitreousselenium Xerographic surface. The sensitivity of the xerographic memberor surface is such, however, that it performs satisfactorily withsubstantially all conventional phosphor light emitters.

While this invention has been described in preferred form, it is to beunderstood that modifications thereof may be made without departing fromthe ambit of the invention.

What is claimed is:

1. A Xerographic reproducing apparatus including in combination aXerographic plate journaled for rotation,

charging means positioned to impose a uniform electrostatic charge onthe surface of said xerographic plate, support means for supporting copysubstantially in a plane, means for scanning copy supported by saidsupport means and for projecting an image thereof onto the xerographicplate, whereby to form an electrostatic latent image of copy on saidxerographic plate,

developing means to develop an electrostatic latent image, whereby toform a xerographic powder irnage of copy on said Xerographic plate,

and image transfer means to transfer a Xerographic powder image tosupport material,

said last recited means including sheet feeding means for superposingsheet material onto a Xerographic powder image on said xerographic plateand transfer means for causing a Xerographic powder image to adhere tosheet material, pick-off means to separate sheet material from saidXerographic plate after image transfer,

and means actuated in accordance with the rotational position of theXerographic plate to initiate operation of said sheet feeding means andsaid pick-off means in timed relation.

2. In a Xerographic machine,

the combination of a Xerographic plate journaled for rotation,

charging means positioned to apply a uniform electrostatic charge tosaid xerographic plate,

a copy board for supporting copy substantially in aA plane.

a scanning means having a lens positioned to project an image of copy onsaid copy board onto said Xerographic plate to form an electrostaticlatent image thereon,

developing means positioned to effect development of an electrostaticlatent image on said Xerographic plate,

a container for sheet material,

sheet feed means positioned to feed sheet material seriatim from saidcontainer to said Xerographic plate,

transfer means positioned to effect transfer of a developedelectrostatic latent image from said xerographic plate to sheetmaterial,

pick-off means positioned adjacent to said transfer means to effectremoval of sheet material from said xerographic plate,

drive means connected to said xerographic plate to rotate saidxerographicplate, said drive ymeans being l@ connected to said scanningmeans to actuate said scanning means to scan copy at a predeterminedspeed relative to the movement of said xerographic plate, and programmermeans driven by said drive means to actuate said sheet feed means andsaid pick-off means in timed relation to the actuation of said scanningmeans. 3. In a xerographic machine, the combination of a Xerographicplate mounted for rotation, charging means positioned to apply a uniformelectrostatic charge to said Xerographic plate, a copy board forsupporting copy substantially in a plane, scanning means including amovable lens to project an image of copy yon said copy board onto saidxerographic plate, said movable lens being arranged to traverse theplane of said copy board by movement from a start-of-scan position to anend-of-scan position, developer means positioned to develop anelectrostatic latent image on said Xerographic plate, a container forsheet material, sheet feed means positioned to feed sheet materialseriatim from said container into contact with said Xerographic plate,transfer means positioned to eect transfer of a developed image fromsaid xerographic plate onto sheet material, pick-off means positioned`adjacent said transfer means to remove sheet material from saidXerographic plate, drive means connected to said Xerographic plate forrotating said Xerographic plate, said drive means being connected tosaid movable lens for moving said movable lens through a predeterminedpath from a start-of-scan position to an end-of-scan position in timedrelation to the movement :of said xerographic plate, said driving meansincluding means to return said movable lens from its end-of-scanposition to its start-of-scan position, and means connected to saidsheet feed means to effect feeding of sheet material to said Xerographicplate in timed relation with the rotational position of said Xerographicplate. 4. A Xerographic copying apparatus including a Xerographic platemounted for rotation,

charging means positioned adjacent said Xerographic plate for applyingan electrostatic charge on said Xerographic plate, Ia copy board forsupporting copy substantially in a plane, a slotted light shieldpositioned adjacent the surface of said Xerographic plate,

. lens means mounted for movement in a path to traverse the plane ofsaid copy board from a start-of-scan position to an end-of-scanposition, to project an image of copy on said copy board through saidslotted light shield `onto said xerographic plate to form anelectrostatic latent image of copy on said xerographic plate,

developing means positioned to develop an electrostatic latent image onsaid Xerographic plate,

a container for sheet material,

sheet feed means positioned to feed sheet material seriatim from saidcontainer into contact with said Xerographic plate,

transfer means positioned to effect transfer of a developed powder imagefrom said Xerographic plate onto sheet material,

pick-off means positioned adjacent said transfer means to effect removalof sheet material from said xerographic plate,

drive means connected to said Xerographic plate for rotating saidxerographic plate,

and scan control means connected to said drive means for moving saidlens means from said start-of-scan position to said end-of-scan positionto scan copy in timed relation to the movement of said Xerographic plateand to return said lens means to said startof-scan position,

said scan control means also being connected to said sheet feed means toeffect the feeding of sheet material into contact with a developed imageon said Xerographic plate and for actuating said pick-off means toremove sheet material from said Xerographic plate.

5. A xerographic machine including a xerographic plate mounted forrotation,

charging means positioned to apply a uniform electrostatic charge onsaid Xerographic plate,

a copy board for supporting copy,

a slotted light shield positioned adjacent the surface of saidXerographic plate,

lens means mounted for movement in a p-ath to scan the optical imagepath from said copy board to there- `by project an image of copy throughsaid slotted light shield onto said xerographic plate,

movable illuminating means mounted for movement to traverse the plane ofsaid copy board,

developing means positioned to develop an electrostatic latent image onsaid Xerographic plate,

a container for sheet material,

sheet feeding means operatively positioned adjacent said container tofeed sheet material seriatim into contact with said Xerographic plate,

transfer means positioned to effect transfer of a deve oped powder imagefrom said Xerographic plate to sheet material,

pick-off means positioned adjacent said transfer means to effect removalof sheet material from said xerographic plate,

drive means connected to said Xerographic plate, said lens means andsaid illuminating means to drive said Xerographic plate, said lens meansand said illuminating means at predetermined speeds relative to eachother, said lens means and said illuminating means being moved fro-moriginal starting positions through predetermined paths to form anelectrostatic latent image on said Xerographic plate during rotationthereof,

said drive means including means to return said lens means and saidilluminating means to their respec- `tive starting positions,

and control means connected to said Xerographic plate to operate intimed sequence to the movement of said xerographic plate to effectoperation of said sheet lfeeding means and said pick-off means.

6. In a Xerographic machine,

the combination of a Xerographic plate mounted for rotation,

Icharging means positioned to apply a uniform electrostatic charge onsaid Xerographic plate,

a copy board for supporting copy substantially in a plane,

scanning means including lens means mounted for movement to traverse theplane of said copy board to expose the charged surface of saidXerographic plate to an image of copy on said copy board, whereby toform an electrostatic latent image of copy on the Xerographic plate,

developing means positioned to develop an electrostatic latent image onsaid Xerographic plate,

a container for sheet material,

sheet feed means positioned to feed sheet material seriatim from saidcontainer into contact with said Xerographic plate,

transfer means positioned to effect transfer of a developed image fromsaid xerographic plate to sheet material,

pick-off means positioned to remove sheet material from said Xerographicplate,

`drive means connected to said Xerographic plate and said lens means tomove said Xerographic plate and said lens means at predetermined speedsrelative to each other,

and control means connected to said drive means to effect operation ofsaid sheet feed means in timed relation to the rotational position ofsaid xerographic plate.

7. In a Xerographic machine,

the combination of a xerographic plate journaled for rotation, Y

charging means positioned to apply a uniform electro static charge onsaid Xerographic plate,

a copy board for supporting copy substantially in a plane,

a scanning means having a light source and a movable lens positioned toproject an image of copy on said copy board onto said Xerographic plate,

developing means positioned to effect development of an electrostaticlatent image formed on said Xerographic plate,

a container for sheet material,

sheet feed means positioned to feed sheet material seriatim from saidcontainer into contact with said Xerographic plate,

transfer means positioned to effect transfer of a developedelectrostatic latent image from said Xerographic plate to sheetmaterial,

pick-off means positioned adjacent said transfer means, said pick-offmeans being adapted to pick off sheet material from said Xerographicplate,

drive means connected to said Xerographic plate to rotate saidXerographic plate,

said drive means including means to effect movement of said movable lenswhereby said lens is moved across the plane of said copy board toproject an image of copy onto said xerographic plate as it is rotated toform an electrostatic latent image,

and said drive means further including means to effect operation of saidsheet feed means in timed relation to the formation of an electrostaticlatent image on said Xerographic plate whereby sheet material isadvanced to said Xerographic plate to coincide with the position of adeveloped electrostatic latent image on said Xerographic plate.

8. A xerographic reproducing apparatus including in combination aXerographic plate journaled for rotation,

charging means positioned to impose a uniform electrostatic charge onthe surface of said Xerographic plate,

support means for supporting copy,

means for scanning copy supported by said support means and forprojecting an image thereof onto the xerographic plate, whereby to forman electrostatic Ilatent image of copy on said Xerographic plate,

ydeveloping means to develop an electrostatic latent image, whereby toform a Xerographic powder image of copy on said Xerographic plate,

and image transfer means to transfor a xerographic powder image tosupport material,

said last recited means including sheet feeding means 4for superposingsheet material onto a Xerographic powder image on said Xerographic plateand transfer means for causing a Xerographic powder image to adhere tosheet material,

pick-off means to separate sheet material from said Xerographic plateafter image transfer,

and means actuated in accordance with the rotational position o-f theXerographic plate to initiate operation of said sheet feeding means andsaid pick-off means in timed relation.

9. In a xerographic machine,

the combination of a xerographic plate journaled for rotation,

charging means positionedI to apply a uniform electrostatic charge tosaid Xerographic plate,

a copy board for supporting copy,

a scanning means having a lens positioned to project an image of copy onsaid copy board onto said xerographic plate to form an electrostaticlatent image thereon,

developing means positioned to eiect development of an electrostaticlatent image on said Xerographic plate,

a container for sheet material,

sheet feed means positioned to feed sheet material seriatim from saidcontainer to said Xerographic plate,

transfer means positioned to effect transfer of a developedelectrostatic latent image from said Xerographic plate to sheetmaterial,

pick-off means positioned adjacent to said transfer means to effectremoval of sheet material from said xerographic plate,

drive means connected to said xerographic plate to rotate saidXerographic plate, said drive means being connected to said scanningmeans to actuate said scanning means to scan copy at a predeterminedspeed relative to the movement of said xerographic plate,

and programmer means driven by said drive means to actuate said sheetfeed means and said pick-off means in timed relation to the actuation ofsaid scanning means.

References Cited in the file of this patent UNITED STATES PATENTS998,663 Wood July 25, 1911 2,123,151 Petit et al. July 5, 1938 2,153,186Henderson Apr. 4, 1939 2,211,766 Brown Aug. 20, 1940 2,703,280Butterfield et al. Mar. l, 1955 2,781,705 Crumrine et al. Feb. 19, 1957FOREIGN PATENTS 579,513 Canada July 14, 1959

